Recovery of terephthalate diesters from glycol residues

摘要

There is described a process for improving the yield of difunctional ester in a process of recovering monomer components from condensation-type polyester resins such as polyethylene terephthalate by converting terephthalyl monomers and oligomers present in ethylene glycol still bottoms to terephthalate diester, such as dimethyl terephthalate. This is accomplished by treating the terephthalyl monomers and oligomers with a mixture of an alcohol and an alkali metal hydroxide at a temperature up to the boiling point of the alcohol.